1. Field of the Invention
The present invention relates to a laser diode and a method of fabricating the same, and more particularly, to a laser diode having column-shaped nano patterns and a method of fabricating the laser diode.
2. Discussion of the Background
In optical communications or other applications in which a wavelength range is extremely limited, a distributed feedback (DFB) laser, distributed Bragg reflector (DBR) laser, or Bragg reflector (BR) laser may be used. A conventional DFB laser diode has a layer having a periodically concavo-convex portion, e.g., a concavo-convex portion with a stripe shape, formed along an active layer and reflects light on the layer, thereby implementing a single mode laser.
Such a laser diode may be fabricated by stopping crystal growth of a semiconductor layer, forming a concavo-convex portion thereon, and then restarting the semiconductor layer growth again. However, the semiconductor layers cannot be continuously grown, and therefore, the process of growing semiconductor layers may be complicated.
Alternatively, a laser diode may be fabricated by forming a concavo-convex portion on a surface of a semiconductor layer which has been completely grown. One technique for forming a concavo-convex portion on a surface of an InP-based semiconductor layer has been disclosed by Kennedy et al. (see Extended Abstracts of the 2006 International Conference on Solid State Devices and Materials, 2006, B-3-6, p262-263).
Studies on a DFB (or, DBR or DR) laser diode have been conducted. Particularly, studies on a single mode DFB laser having a wavelength of about 400 nm have been conducted.